AOPA Pilot - May 2013

AOPA Pilot

The press is taking notice of the new digital fuel level senders in the new Cirrus aircraft.

In this case AOPA Pilot and Tom Horne

Here the new fuel level  senders are being discussed with the integration to the standard Cirrus Garmin Perspective Panel.

We agree that accurate fuel level makes it much easier to manage fuel and payload 

The dialogue we started a year and a half ago 

That accurate fuel level in aviation will allow for a higher level of integration, and relieve pilot workload

These innovations are reaching the light of day and in now in production

Tank level balancing and enriched warnings are now reality

The "Zero Fuel" Myth - You know, Fuel Gauges only Need to be Accurate when Empty

You don't really need to know what happened after this true Accident Narrative - It is evident from the beginning.

Picture Draw Jerel Draw,  jereldye.com

Prior to the incident, I received an instructional ride and completed my C-172 checkout. I then flew with a passenger and solo, three flights, for a total of 5.3 hours in the bird.

In all three of those flights.

• I observed erroneous fuel quantity indications,
• Intermittent cycling of the fuel gauges to zero.
• LH Fuel Low Level Warning light coming on intermittently. 

An [instructor] told me this condition was well  known, typical for this aircraft and not uncommon for general aviation aircraft.

I discussed the erroneous fuel quantity indications with the Chief Pilot, and asked
him if I should write them up. 

He said no, that the indications were within the spec, which requires only that they
read accurately when empty.

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The statement that fuel gauges only read accurately when empty is repeated so many times in the aviation dialog.

 You would almost have to believe it is true.

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Actually far from it.

• It is a comment you hear repeated by many pilots, the magazines & AOPA / FAA Safety Briefs.  

• It is not uncommon to have bad fuel gauges in aviation, it is frighteningly almost the rule.  

What is true: 

• Fuel gauges are "Required" aircraft instruments for powered aircraft.

• They are required to be functional by design and in operation on the aircraft   -  Specifically:

• Read fuel level from FULL to EMPTY.  
• EMPTY needs to be calibrated at "Zero Usable Fuel"
• The Zero Usable Fuel is the fuel level,  where in the worst condition - fuel cannot be drawn from the tank.

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Designing, Maintaining or Flying an aircraft with bad or in-operative fuel gauges is illegal.  

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Why is it surprising that so many GA pilots run out of fuel.

I think the answer is obvious.

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Selecting your Fate - Choosing the Proper Tank.

We read so many aviation fuel starvation accident reports and the published responses from AOPA and others  

"On March 12, 2005, a 24,611-hour ATP made a forced landing in an open field after a total loss of engine power while on a visual approach to Runway 13 at Lancaster Airport in Lancaster, Texas. He and the one passenger were not injured.
The pilot did not visually check the fuel tanks prior to takeoff and could not recall "what the fuel gauges indicated"  during the flight.
He thought both auxiliary fuel tanks were full, and both main fuel tanks were almost full.  While descending for the approach, the pilot moved the fuel selector valve from the left main tank to the right main tank" 

Here is where we believe accurate or at least functional fuel level comes into play - The pilot did not look at his gauges - if he had,  and they were operating as designed - He probably would not have switched to an empty fuel tank.

Very shortly after, the engine quit. The pilot unsuccessfully attempted to restart the engine by switching the fuel selector valve back to the left tank and cycling the throttle.  

It is interesting that the neither the FAA nor NTSB tested this aircraft's fuel gauges for operation.  They only tested the engine. 

   We have all become complacent that aircraft fuel gauges can offer little or no assistance to fuel starvation in our mode of transportation.

One aircraft manufacturer has looked at this issue and did something about it - why guess if the tank you are switching to holds fuel.   

Cirrus Aircraft has incorporated accurate fuel level - and with accurate fuel level you may eliminate switching to an empty tank.   

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